Detailed Field Research Articles

Late Triassic extension of thickened lithosphere of the East Kunlun orogenic Belt, northern Tibetan Plateau: Evidence from the geochemistry and geochronology of mafic magmatism

The East Kunlun Orogenic Belt (E-KOB) evolved into an extensional tectonic setting with plenty of mafic magmatism after the closure of the Paleo-Tethys Ocean. However, the deep tectonic system and geodynamic processes in this context still need further clarification. The detailed field geological, petrological, geochronological and geochemical works carried out on the Yeniugou gabbros in this study could provide key evidence for clarifying this issue. The gabbros are predominantly composed of clinopyroxene, orthopyroxene, plagioclase, olivine and ilmenite. Zircon U–Pb dating results suggest that their formation at ca. 209–207 Ma. Characterized by a relatively low SiO2 content and a moderate total alkaline content, these rocks are classified as alkalic to subalkaline series. High values of Mg# (42.2–59.4) and high concentrations of compatible elements (V, Cr, Co, Ni) suggest that their parent magma was generated through high partial melting of a lithospheric mantle source. The left-leaning rare earth element distribution patterns, combined with the characteristic spikes of Nb-Ta, indicate that they were originated from the lithospheric mantle metasomatized by subducting components. The positive zircon εHf(t) values (0.1–5.7), along with elevated Nb/La ratios (0.45–0.67), further confirm a small amount of asthenosphere mantle contribution. Elevated Zr/Y ratios, plus a slightly positive correlation between Alz and TiO2 in clinopyroxene, imply that they formed within an extensional setting, where the upwelling of the asthenospheric mantle provided heat for partial melting of the metasomatic lithospheric mantle. Combined with previous data, we suggest that E-KOB underwent delamination of thickened lithosphere in the late Triassic, following the closure of the Paleo-Tethys Ocean.

Probabilistic, scenario-based hazard assessment for pyroclastic density currents at Tungurahua volcano, Ecuador

We assess the volcanic hazard posed by pyroclastic density currents (PDCs) at Tungurahua volcano, Ecuador, using a probabilistic approach based on the analysis of calibrated numerical simulations. We address the expected variability of explosive eruptions at Tungurahua volcano by adopting a scenario-based strategy, where we consider three cases: violent Strombolian to Vulcanian eruption (VEI 2), sub-Plinian eruption (VEI 3), and sub-Plinian to Plinian eruption (VEI 4–5). PDCs are modeled using the branching energy cone model and the branching box model, considering reproducible calibration procedures based on the geological record of Tungurahua volcano. The use of different calibration procedures and reference PDC deposits allows us to define uncertainty ranges for the inundation probability of each scenario. Numerical results indicate that PDCs at Tungurahua volcano propagate preferentially toward W and NW, where a series of catchment ravines can be recognized. Two additional valleys of channelization are observed in the N and NE flanks of the volcano, which may affect the city of Baños. The mean inundation probability calculated for Baños is small (6 ± 3%) for PDCs similar to those emplaced during recent VEI 2 eruptions (July 2006, February 2008, May 2010, July 2013, February 2014, and February 2016), and on the order of 13 ± 4% for a PDC similar to that produced during the sub-Plinian phase of the August 2006 eruption (VEI 3). The highest intensity scenario (VEI 4–5), for which we present and implement a novel calibration procedure based on a few control points, produces inundation areas that nearly always include inhabited centers such as Baños, Puela, and Cotaló, among others. This calibration method is well suited for eruptive scenarios that lack detailed field information, and could be replicated for poorly known active volcanoes around the world.

An open dataset for individual tree detection in UAV LiDAR point clouds and RGB orthophotos in dense mixed forests

We present an open access dataset for development, evaluation, and comparison of algorithms for individual tree detection in dense mixed forests. The dataset consists of a detailed field inventory and overlapping UAV LiDAR and RGB orthophoto, which make it possible to develop algorithms that fuse multimodal data to improve detection results. Along with the dataset, we describe and implement a basic local maxima filtering baseline and an algorithm for automatically matching detection results to the ground truth trees for detection algorithm evaluation.

Rare occurrence of only female flowers suggests a lack of sexual reproduction and potential clonality of the seagrass Halophila baillonii Asch. on the Pacific coast of Costa Rica

Halophila baillonii Asch. is a rare seagrass species found in the Caribbean, Atlantic, and Eastern Tropical Pacific (ETP). It is listed as Vulnerable in the IUCN Red List yet very little is known about its dispersal mechanisms. For this study, samples were collected at five sites on the Pacific coast of Costa Rica. Each site was visited once between 2019 and 2021 as part of a larger molecular study. At each site, H. baillonii foliar shoots were manually collected along three transects. Presence of flowers or fruits was assessed for 1292 foliar shoots using a dissecting microscope. Additionally, sediment samples were collected to assess seed density at three of the sites. Flowering frequency was very low overall (0.7 %), flowers were only found at two of the five sites, and only female flowers were present. There were no fruits or seeds at any of the sites. This is the first report of H. baillonii flowering on the Pacific coast of Costa Rica and within the ETP. Meanwhile, H. baillonii flowers of both sexes and fruits have been found from limited sampling efforts at multiple sites in the Caribbean and Brazil. The findings of this study suggest a lack of sexual reproduction and potential clonality of the seagrass H. baillonii on the Pacific coast of Costa Rica. This supports the recent notion that H. baillonii is the first non-native seagrass in the ETP, yet more detailed field and molecular studies are needed.

Simulation study on flow field regulation of flotation column with stirring device

ABSTRACT Flow field regulation plays an important role in the optimization of column flotation units with agitation function. This paper aims to discuss the regulating effect of baffle design on the flow field in stirred column flotation units by numerical simulation. A series of geometric models of changing baffle structure and layout were established, and detailed flow field simulation analysis was carried out by using COMSOL software. The results show that the internal flow field of the traditional standard cylindrical tank will cause the solid particles to adhere to the wall movement and the bubbles to the middle area, resulting in the uneven distribution of particles and bubbles, and the internal flow field is not conducive to the mineralization process and the stability of the foam layer. This limitation can be significantly improved by introducing baffles. The results show different baffle shapes and layouts are as follows: wide and narrow on top, narrow on the bottom and wide on top, and only arranged at the bottom of the column body, can increase the average turbulent kinetic energy in the collision zone by 22%, 46% and 43%, and the average turbulent dissipation rate by 18%, 43% and 36%, respectively, while maintaining the turbulence intensity in the transport zone. Among them, the baffle plate with wide top and narrow bottom has the best effect. Arranging baffles with a length shorter than 2/3 of the height of the cylinder at the upper part inside the cylinder can also enhance the turbulence intensity in the collision zone, but at the same time, it also increases the turbulence intensity in the transport zone. Moreover, as the length of the baffle decreases, the enhancement effect becomes stronger. Since this method significantly affects the transport zone, it is more suitable for columnar mixing devices. The study also reveals that by adjusting the proportion of wide and narrow baffles, the center of the turbulent region can be laterally shifted to the short baffles, and the flow field distribution can be adjusted. Meanwhile, with the increase in the number of long baffles, the intensity of the flow field in the device will gradually decrease. By moving the center of the turbulent region to the side inlet, the particle dispersion can be accelerated, but in general, the particles will accumulate toward the region with lower turbulence intensity. These findings have important guiding significance for the design and optimization of the flow field of the stirred column flotation unit, which is helpful in improving the agitation uniformity and flotation efficiency.

Measurements of frazil ice flocs in rivers

Abstract. Frazil floc sizes and concentrations have been investigated in a small number of laboratory studies, but no detailed field measurements have been reported previously. In this study, a submersible camera system was deployed a total of 11 times during the principal and residual supercooling phases in the North Saskatchewan, Peace, and Kananaskis rivers to capture time-series images of frazil ice particles and flocs. Images were processed to accurately identify flocs and to calculate their sizes and concentrations. Key hydraulic and meteorological measurements were collected, and air–water heat fluxes were estimated to investigate their influence on floc properties. A lognormal distribution was found to be a good fit for the floc size distribution. The mean floc size ranged from 1.19 to 5.64 mm and the overall mean floc size was 3.80 mm. The mean floc size decreased linearly as the local Reynolds number increased. The average floc number concentration ranged from 1.80×10-4 to 1.15×10-1 cm−3. The average floc volumetric concentration ranged from 2.05×10-7 to 4.56×10-3 and was found to correlate strongly with the fractional height above the river bed. No significant correlations were found between the air–water heat flux and floc properties. Time series analysis showed that during the principal supercooling phase, floc number concentration and mean size increased significantly just prior to peak supercooling and reached a maximum near the end of principal supercooling. During the residual supercooling phase, the mean floc size did not typically vary significantly even 2.5 h after the residual phase had ended and the water temperature had increased above 0 °C.

Erosion of mangrove dominated muddy coasts in Vietnam and Indonesia: Processes and accelerating factors

Although there have been extensive studies of the erosion of mangrove-dominated muddy coasts, the information on the processes and drivers of erosion at fine scales of analysis is still lacking. Without this knowledge, the existing efforts to minimize erosion are just piecemeal solutions that only address the symptoms of the erosion process. The coastlines of the Mekong Delta in Vietnam (VMD) and Brebes Regency in Indonesia have been selected as case studies to address this issue. The aim of the paper is to document coastal erosion and the factors that accelerate the erosion process. This is achieved by using the participatory diagramming technique, which combines the analysis of photographs of erosion sites taken during field trips, detailed field observations, and responses from semi-structured interviews with erosion-affected communities in VMD and Brebes Regency, Indonesia. The results show that five dominant erosion processes identified in these two regions were burrow-induced erosion, clearcut-induced erosion, farming-induced erosion, pond-induced erosion, and boating-induced erosion. Of the five erosion processes, human activities have altered the characteristic of the mangrove forests, and are likely to have exposed areas to erosion, with wave action providing a tipping point by severely reducing the structural integrity of the coastal soil in sensitive areas and making them susceptible to collapse. However, many other areas in VMD and Brebes Regency, Indonesia have remained stable over time. The methodological approach proposed here appears to be applicable to other mangrove-dominated muddy coasts, which are characteristic of most anthropogenically affected tropical deltas. As human activities are closely linked to forestry policies in Vietnam and Indonesia, enforcement should be strengthened to significantly increase the impact of these policies in controlling coastal erosion and minimize the vulnerability of these areas to erosion.

Biomimetic Wings for Micro Air Vehicles.

In this work, micro air vehicles (MAVs) equipped with bio-inspired wings are investigated experimentally in wind tunnel. The starting point is that insects such as dragonflies, butterflies and locusts have wings with rigid tubular elements (corrugation) connected by flexible parts (profiling). So far, it is important to understand the specific aerodynamic effects of corrugation and profiling as applied to conventional wings for the optimization of low-Reynolds-number aerodynamics. The present study, in comparison to previous investigations on the topic, considers whole MAVs rather than isolated wings. A planform with a low aperture-to-chord ratio is employed in order to investigate the interaction between large tip vortices and the flow over the wing surface at large angles of incidence. Comparisons are made by measuring global aerodynamic loads using force balance, specifically drag and lift, and detailed local velocity fields over wing surfaces, by means of particle image velocimetry (PIV). This type of combined global-local investigation allows describing and relating overall MAV performance to detailed high-resolution flow fields. The results indicate that the combination of wing corrugation and profiling gives effective enhancements in performance, around 50%, in comparison to the classical flat-plate configuration. These results are particularly relevant in the framework of low-aspect-ratio MAVs, undergoing beneficial interactions between tip vortices and large-scale separation.

The Gulf Stream Structure and Meandering Based on the CTD and SADCP Measurements in 1989–1990 and 2014–2015

An review of field studies in the Gulf Stream region carried out by the authors in two periods with a break of 25 years is presented to summarize the results. The studies in the early period included hydrographic surveys in the area of a southern meander of the Gulf Stream (1989) and in the area of dividing of a single jet of the current into separate branches: in the Gulf Stream delta (1990). The second, recent, stage includes on-route surveys with SADCP profiler in 2014–2015 while crossing the meandering Gulf Stream at mid-latitudes to study its detailed high-resolution velocity field structure.

Slope stability analysis of colluvial deposits along the Muketuri-Alem Ketema Road, Northern Ethiopia

Slope failures are a significant natural geohazard in hilly and mountainous regions, often resulting in loss of life and infrastructure damage. The Muketuri-Alem Ketema road in Ethiopia is particularly vulnerable to landslides due to colluvial deposits on steep slopes from the higher northeastern plots to the lower Jemma River valley. This study investigates the characteristics of colluvial soil and evaluates the stability of slopes prone to landslides. It combines geophysical data, penetrometer tests, laboratory analyses, Google Earth images, and detailed field visits to assess the soil and bedrock composition and structure. Numerical methods, including limit equilibrium (Bishop, Janbu, Spencer, and Morgenstern-Price methods) and finite element methods, were used to analyze slope sections under various saturation conditions and simulate different rainfall patterns. The results indicate that the Bishop, Morgenstern-Price, and Spencer methods produce similar safety factors with minimal differences (<0.3%), while the Janbu method shows more significant variation (1.5%–5.6%). Safety factor differences for sections A-A and B-B range from 5.26% to 9.86% and 3.5%–4.7%, respectively. Simulations reveal that short-term saturation significantly reduces the stability of the upper slope layer by 20%–46.76%, and long-term saturation decreases the entire slope section by 26.81%–46.76% compared to dry conditions due to increased pore water pressure and self-weight. Long-term saturation effects, combined with dynamic loads, can further reduce colluvial soil stability by over 50% compared to a dry static state. The finite element method predicts larger failure zones than limit equilibrium methods, emphasizing the need for accurate predictions to characterize slope behavior during failure and inform stabilization decisions. This study provides crucial data for maintaining and planning the Muketuri-Alem Ketema Road, highlighting slope performance over time and the effectiveness of stabilization techniques.

Large variations of dissolved carbon occurred in small ponds within an agricultural watershed

Dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) significantly affect the aquatic carbon budget and ecosystem functions. Small ponds are abundant globally and widely distributed especially in agricultural watersheds, however, the variability of DOC and DIC, along with their driving factors, remains poorly understood, which likely hampers the understanding of carbon cycle of inland waters. The presented study was designed to fill the knowledge gap based on a detailed year-long field investigation via examining DOC and DIC concentrations across ponds with differing functionalities (e.g. sewage ponds, irrigation ponds, and natural ponds) of a typical agricultural watershed in eastern China. Our results found a pronounced impact of human activities on pond DOC and DIC, with higher DOC occurring in sewage ponds (10.84 ± 2.83 mg L−1) and irrigation ponds (9.09 ± 2.57 mg L−1) and peak DIC in irrigation ponds (20.36 ± 2.49 mg L−1) compared to that at natural ponds (DOC: 7.54 ± 2.55 mg L−1; DIC: 11.16 ± 3.85 mg L−1) with less human activity. The positive correlations between DOC/DIC and key environmental variables (e.g. nutrients and chlorophyll-a) further demonstrated that human activity can either directly increase the carbon concentrations via pollutant discharge, or indirectly increase DOC concentration via stimulating primary production. Meanwhile, field measurements found precipitation and temperature play roles in determining the carbon variability. Specifically, precipitation increased the DOC of these ponds via enhancing land-based carbon inputs, and decrease the DIC of irrigation ponds via diluting. Temperature can influence the carbon dynamics through increasing primary productivity and metabolism. Our study underscores the roles of human and natural influences in determining the large variations of DOC and DIC in small ponds, which should be considered to better understand the carbon dynamic variability of human-impacted small aquatic systems.

Activity and motion characteristics on the southern segment of the Red River fault zone, Yunnan province, China

The longer time for recording large earthquakes on a plate boundary fault, the better that understanding of large earthquake rupture behavior and seismic hazard on the fault zone. However, large earthquakes (M ≥ 7) are rarely recorded on the boundary fault with slow slipping rate, such as the Red River fault zone (RRFZ), which is an important plate boundary fault that marks the southwestern boundary of the Yangtze platform or south China block. There have been no large earthquake records on the southern segments (including the segment in Vietnam) of the RRFZ since historical earthquake records began in 886 AD, except the 1652 Midu M 7 earthquake and the 1925 Dali M 7 earthquake on the northern segment. The southern segment of the RRFZ will not have a large earthquake in the future or as a large earthquake seismogenic zone with a long period of recurrence, remains controversial, in part because of the absence of constraints from geological evidence. This controversial seriously restricts the risk assessment of future large earthquakes on the southern segment of the RRFZ. By careful interpretations of high resolution remote sensing images, in combination with a detailed field geological and geomorphic survey, we found a series of fault valleys and bedrock outcrops from Gasha toYaojie and Yuangjiang to Hekou on the southern segment of the RRFZ. Multiple trench excavation and radiocarbon dating sample analyses show that the mid valley trace in the southern segment of the RRFZ is an active fault. Geological and geomorphic evidence from Gasha to Yaojie and Yuanjiang to Hekou indicate that the mid valley trace in the southern segment of the RRFZ exhibits dip slip and dextral strike slip motion characteristics. This result is inconsistent with those of previous studies that the mid valley trace is purely strike slip. Furthermore, trenches opened on the range front trace in the southern segment of the RRFZ in Ejia are found to still be active, differing from previous studies. Thus, the seismic hazard on the southern segment of the RRFZ should be reevaluated.

Literature-based database to inform policy making on marine plastic pollution in ASEAN+3

The ASEAN+3 countries urgently need to present actual data on the state of their marine plastics pollution, so that they can respond to the criticisms of being the top-5 global sources of marine plastics based on modeled predictions, as well as to develop effective response policies based on sound data. While the research outputs on marine plastic pollution have increased spectacularly across these countries, their overall resource capacity to access the data remains lacking. This study describes a robust framework developed to use &amp;gt;700 peer-reviewed research publications from the region that can inform policy-making. First, detailed metadata fields were developed for this database focused on extracting information from the publications that are relevant to regional policy questions being asked to adequately respond to the threats posed by marine plastics. Second, the curation of research publications in this database greatly depended on a team of regional researchers, who were apt in the subject matter and a native language speaker. The latter was critical in the capture of non-English articles to boost the quality of database. Some of the key findings from the broad analyses included the rapid increase in research efforts on marine plastics between 2014 and 2021, which coincided with the growing concerns of this environmental crisis, the dominant publication language was English despite the diversity of countries, and the dominant research topic appeared to be of policy response measures. Overall, the database produced adequate and immediate data, where policy-makers can leverage for urgent actions. For example, the output on the status of marine plastic pollution is ever-increasing, but the region could start to focus on knowledge gaps (e.g., sampling in critical sensitive habitats like seagrasses and coral reefs). Finally, this study presented a comprehensive summary of the current state of marine plastic pollution and knowledge gaps (e.g., technical capacity and equipment) of the region that can facilitate discussions among target audience including the governments as well as international and regional regulating bodies, the research community and plastic waste management professionals.

A comprehensive comparison of film cooling characteristics of shaped holes on the leading edge of rotating blade

This study numerically investigates the cooling characteristics and flow features of various hole geometries on the rotating blade leading edge. A comprehensive comparison of cooling effectiveness, heat transfer coefficients, net heat flux reduction, and discharge coefficients is conducted among laidback fan-shaped, fan-shaped, laidback, cone holes, and cylindrical holes with two different diameters. Detailed flow and thermal field analysis reveals the impact of geometry on cooling performance. The blade rotational speed is 600 rpm, with a Reynolds number of 12.4 × 104, blowing ratios from 0.5 to 2.0, and fixed injection and spanwise angles at 90° and 30°. Shaped holes share a uniform hole exit-to-inlet area ratio, and cylindrical holes match their inlet or exit areas. The RANS equations were closed using the SST k-ω turbulence model coupled with the Gamma Theta transition model, and an unstructured grid of 13.0 million cells was employed to attain relatively accurate predictive results. Results show that the lateral expansion on the leading edge significantly enhances cooling performance, with fan-shaped holes outperforming others, especially at high blowing ratios. Additionally, cooling effectiveness and discharge coefficient on the leading edge correlate strongly with hole geometric parameters. Shaped holes with equal area ratios show similar discharge coefficients. Cooling effectiveness at high blowing ratios is proportional to the effective exit width, provided that the coolant flows smoothly without severe lift-off.

Lancang Fault Assists Block Extrusion in Southeastern Tibet During Early‐Middle Miocene

AbstractThe tectonic and topographic evolution of the southeastern Tibetan Plateau based on low‐temperature thermochronology data is controversial, especially whether it is tectonically‐ or climatically‐controlled, especially along the Lancang fault (LCF) that links the flat central plateau to the west with the high relief southeastern Tibetan Plateau to the east. To explore the tectonic evolution of the LCF and its role in the tectonic and topographic evolution of the southeastern Tibetan Plateau, we carried out detailed field investigation and low‐temperature thermochronology (AHe, AFT, and ZHe) analyses. Field evidence indicate that the northern LCF splits into two branches, the Yangda‐Yaxu and Baqing‐Leiwuqi faults, the latter striking N50°W and dipping to the SW at ∼55°, exposing &gt;100 m‐wide fault rocks composed of a fault damage zone, breccia, and gouge. New thermochronology data and thermo‐kinematic modeling results suggest rapid exhumation of the region located between these two fault branches during ∼22–10 Ma at an exhumation rate of ∼1.57 km/Ma, compared to slow cooling prior to 22 Ma and since 10 Ma. We propose that internal anti‐clockwise block rotation triggered rapid local exhumation, and that the final merging of different parts of the LCF during the Early‐Middle Miocene assisted the southeastward escape of Sundaland, which profoundly affected the evolution of the regional geomorphology.

JAMES BUTTLE REVIEW: Interflow, subsurface stormflow and throughflow: A synthesis of field work and modelling

AbstractInterflow, throughflow and subsurface stormflow are interchangeable terms that refer to the lateral subsurface flow above a restricting layer of lower hydraulic conductivity that occurs during and following storm events. Interflow (used here) is a more dominant process in steeper catchments with high infiltration capacity soils overlying a more impermeable soil or geologic layer. Interflow as a runoff process was first recognised in the early 1900s, yet hydrologists still struggle to predict its occurrence, persistence, importance, interaction with other streamflow generation processes, and potential to connect to valleys and streams during and following storms. We review the history of interflow research and address some of the challenges in understanding its role in runoff production. We argue that characterising the controls on interflow initiation and occurrence relies on detailed field observations of subsurface properties, which exist only in limited experimental settings. This data shortcoming contributes to our inability to predict interflow or determine its contribution to streamflow more broadly. There remain many opportunities to advance our understanding of interflow that include both modelling and experimental or observational approaches in hydrology.

Rural heat island effect of centralized residences in China: Mitigation through localized measures

China has implemented a Centralized Rural Policy since 2004 to enhance energy efficiency. However, this has led to the potential creation of a Rural Heat Island (RHI) effect, which could diminish outdoor thermal comfort and increase building energy consumption during hot summers. While most studies on heat island effect focus on spatiotemporal variations and heat mitigation measures, there is limited research on rural areas, particularly the special layout of rural residences. Additionally, most studies only consider the outdoor environment, overlooking indoor thermal comfort and building energy consumption. Therefore, in order to investigate the RHI effect and assess the efficacy of localized heat mitigation measures, this study analyzed 22 types of courtyard layout patterns in a typical centralized village in northern China through detailed field measurements and performance simulations. The results show an obvious heat island effect in the rural centralized residences, where residential zones recorded average temperatures of 1.6 °C higher than those of rural boundaries. Courtyards featuring a south wing significantly alleviated outdoor thermal stress, reducing the discomfort time of extreme Physiological Equivalent Temperature (PET) by 1.5 h compared to those courtyards with a wall. Among the four localized heat mitigation measures examined, the featured black fabric shade performs best for its effectiveness in mitigating outdoor thermal stress, capable of reducing the courtyard's maximum Mean Radiant Temperature (Tmrt) by 21.5 °C and decreasing the duration of extreme PET by 2 h. Photovoltaic modules installed on the roof not only generate energy but also alleviate outdoor thermal stress, reducing the maximum Tmrt by 12.9 °C and lowering 23 % to 28 % daily energy demand, making them highly suitable for deployment in rural areas with high rates of energy poverty. The simulated results indicate that these localized heat mitigation measures mutually reinforce each other in reducing the RHI effect. The combination of four heat mitigation measures can reduce PET by up to 20 % and EUI by up to 44 % compared to the original courtyard. Incorporating these localized strategies into planning practice enables rural planners and policymakers to develop effective interventions against the RHI effect.

An experimental study of vortex evolution around an offshore stationary dual-chamber oscillating water column converter

The Oscillating Water Column (OWC) is a promising Wave Energy Converter (WEC) due to its practicality and efficiency. Conventional single-chamber OWCs exhibit constraints in extracting energy over diverse wave periods, while dual-chamber OWCs demonstrate enhanced adaptability, leading to improved energy capture rates. This study investigates an offshore stationary dual-chamber OWC with an underlying transverse channel designed to facilitate wave ingress and augment energy extraction. Experiments across various wave periods reveal that dual-chamber OWCs with transverse channels achieve superior wave energy extraction compared to single-chamber counterparts. Time-resolved particle image velocimetry (TR-PIV) is employed for detailed flow field measurement to elucidate the complex hydrodynamic processes. Analysis of the water column oscillation and flow dynamics reveals an intensified interaction between hydrodynamic processes in the dual chambers, especially with elongated transverse channels. The Ω method is used to examine vortex evolution, indicating heightened complexity in vortex formation within dual-chamber OWCs compared to single-chamber OWCs. Notably, large-scale vortices emerging in the forward chamber impede oscillation and diminish energy extraction efficiency. Optimizing the design of transverse channel entries, frontal walls, and internal chamber corners is crucial to mitigate flow separation and vortex generation, thereby enhancing overall energy extraction performance.

Enhancing wind field resolution in complex terrain through a knowledge-driven machine learning approach

Wind energy, an essential component in the fight against climate change, relies heavily on precise, detailed wind field simulations to optimize wind farms, particularly in complex terrain with intricate wind patterns. However, conventional high-resolution simulations come with a hefty computational cost, limiting their applicability in real-time decision-making. This research addresses this challenge by proposing a machine learning-driven, computationally efficient approach utilizing a modified Generative Adversarial Network. The contribution of this work is threefold. Firstly, we provide access to a unique high-resolution dataset of wind fields in complex terrain. Secondly, we introduce a knowledge-based modification to the loss function, ensuring that the algorithm captures crucial characteristics of the flow within complex terrains. Finally, we demonstrate the potential of our approach to enhance wind flow resolution in real-life wind farms. Through this, our method delivers comparable accuracy to high-resolution simulations while substantially reducing computational demands. This advancement greatly enhances the accessibility and efficiency of high-resolution wind field simulations, facilitating real-time optimization of wind farms. Moreover, we illustrate that by designing an appropriate loss function informed by domain knowledge, we can mitigate the need for adversarial training.

Effect of symbiotic microbiota and arginine on host plant selection by the tea green leafhopper in tea cultivation

The tea green leafhopper (TGLH), Empoasca (Matsumurasca) onukii Matsuda, poses a significant challenge to tea cultivation in East Asia because of its ability to infest specific tea plant cultivars. Here, we investigated the complex interactions between TGLHs, various tea cultivars, and their symbiotic microbiota, especially the effect of arginine on host selection. A detailed two-year field study involving 16 tea cultivars, coupled with controlled laboratory and field experiments, was conducted to establish a clear link between TGLH infestation and the arginine content of tea plants. Metagenomic analysis revealed a predominance of bacterial taxa in TGLHs, primarily from the phylum Proteobacteria, with significant contributions from orders such as Pseudomonadales, Enterobacterales, and Flavobacteriales, which are crucial for the biosynthesis of essential amino acids but lack the argF gene necessary for arginine synthesis. The absence of the argF gene indicates the potential presence of microbial-mediated dietary adaptation strategies in TGLHs. Additionally, our research examines microbial diversity within TGLH populations and confirms the critical role that symbiotic bacteria play in influencing dietary preferences. The results of our study provide insights into the dynamic interplay between pests, plants, and microorganisms. Our findings are preliminary, and further research is needed to explore the potential applications of symbiotic bacteria in sustainable tea cultivation and integrated pest management strategies.